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diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/popcountti2.c b/contrib/llvm-project/compiler-rt/lib/builtins/popcountti2.c
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index 000000000000..79cbb2fb34c0
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+++ b/contrib/llvm-project/compiler-rt/lib/builtins/popcountti2.c
@@ -0,0 +1,43 @@
+//===-- popcountti2.c - Implement __popcountti2
+//----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __popcountti2 for the compiler_rt library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "int_lib.h"
+
+#ifdef CRT_HAS_128BIT
+
+// Returns: count of 1 bits
+
+COMPILER_RT_ABI int __popcountti2(ti_int a) {
+  tu_int x3 = (tu_int)a;
+  x3 = x3 - ((x3 >> 1) &
+             (((tu_int)0x5555555555555555uLL << 64) | 0x5555555555555555uLL));
+  // Every 2 bits holds the sum of every pair of bits (64)
+  x3 = ((x3 >> 2) &
+        (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL)) +
+       (x3 & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL));
+  // Every 4 bits holds the sum of every 4-set of bits (3 significant bits) (32)
+  x3 = (x3 + (x3 >> 4)) &
+       (((tu_int)0x0F0F0F0F0F0F0F0FuLL << 64) | 0x0F0F0F0F0F0F0F0FuLL);
+  // Every 8 bits holds the sum of every 8-set of bits (4 significant bits) (16)
+  du_int x2 = (du_int)(x3 + (x3 >> 64));
+  // Every 8 bits holds the sum of every 8-set of bits (5 significant bits) (8)
+  su_int x = (su_int)(x2 + (x2 >> 32));
+  // Every 8 bits holds the sum of every 8-set of bits (6 significant bits) (4)
+  x = x + (x >> 16);
+  // Every 8 bits holds the sum of every 8-set of bits (7 significant bits) (2)
+  //
+  // Upper 16 bits are garbage
+  return (x + (x >> 8)) & 0xFF; // (8 significant bits)
+}
+
+#endif // CRT_HAS_128BIT